ZOIA video still

‘Making guitar pedals?! Freaking mental!’ – Steve Bragg, Empress Effects, and the ZOIA

Image credit: Empress Effects

"You go down tonnes of rabbit holes": inside the mind of Empress Effects empressario Steve Bragg and his ZOIA.

Much like the twisting, surprising, occasionally frustrating evolutionary path of Empress Effects' ZOIA multi-effects pedal itself, the genesis of this interview actually began nearly three years ago. Empress was releasing its Reverb pedal (it's... a reverb pedal), so we began talking to Steve Bragg, Empress's founder, the Emperor of Empress, if you will.

Various work delays, seismic life events (Bragg's family headcount expanded by one), the inevitable forgetting, followed by the eventual remembering, saw the Reverb launch come and go, to be succeeded in the Empress line-up first by the Echosystem delay pedal and now by the all-encompassing, all-conquering ZOIA (pronounced 'zoy-ya').

And yes, while it runs contrary to E&T's house style, in this instance we are respecting Empress' preferred all-caps approach for ZOIA, as Bragg asked us to do so "pretty Canadian please". It's hard to argue with such a polite request. "And if you want to refer to it in all caps vocally, all you have to do is yell it at the top of your lungs!"

Beginning in 2007 as a one-man operation, working out of Ottawa, Canada, with its famously 'extremely orange' and full-featured Tremolo pedal (which recently celebrated its 10th anniversary with a special limited-edition, sold-out reissue), since that time Bragg and Empress Effects has carefully grown both its product line-up and its staff roster.

Currently offering around 20 different effects and utility pedals, it was the public release of the ZOIA earlier this year that really blew the lid off Empress' – and Braggs' – hitherto untapped 'mad scientist' leanings.

Launched with a teaser video depicting a mysterious entity contained within a laboratory, ZOIA eventually escaped into the wild in mid-April 2019. Since then, the audio influencers of social media have been buzzing with new videos and demos.

Already well-known (and highly regarded) for its traditional guitar effects pedals – where one box essentially does one thing, e.g. tremolo, reverb, delay – Empress' ZOIA is basically a modular synthesizer in pedal form. It takes some of the best Empress algorithms from existing pedals, such as the Reverb, and makes them available for use in any context that the user desires.

In this way, ZOIA can be used to create bespoke effects, synthesizers, MIDI instruments or entire virtual pedal boards, chaining the necessary 'building blocks' of sound together directly on the ZOIA. All programming is done on the pedal, via a grid of multicoloured buttons.

ZOIA also ships with many of the standard (guitar) effects preinstalled as existing 'modules' ready for use, such as a phaser. As Empress says, you don't have to know that phasers are created with a series of all-pass filters. What ZOIA enables is the choice to simply play a pre-installed phaser; to build your own dream phaser design, taking that basic phaser and pimping it out to be exactly how you want it, and then take that phaser and layer an ambient reverb on top of it, add a stutter effect, maybe a resampler, dual loopers, one of which has a lo-fi delay and distortion on it, the ability to control the whole thing via MIDI or CV, then save the result as a single module, and then connect that module to another insane creation (or two, or three, or four) fresh from your brain, until a single guitar note sounds like the gargantuan distant reverberation of an alien electric orchestra tuning up somewhere beyond the Milky Way, a heavenly mesmeric signal beamed back to Earth via a broken satellite connection. Woah.

Plus, if things get too crazy, you can easily peel back all those layers and get back to the warmth and comfort of a good old-fashioned, straight-up, great-sounding phaser effect, no harm done. The only limit really is your imagination. As Empress says, ZOIA is an infinite trick pony.

How did Empress – or, more to the point, Bragg – get to this point of easy-access aural insanity?

"The ZOIA is like a Pure Data or Max/MSP system in a pedal. It's receiving a lot more attention than any of our other pedals ever did," Bragg says. "Basically like Pure Data in a guitar pedal. I guess you could replace stuff [other effects pedals] with it, but I think you'd be disappointed to some extent. It shines a lot more as a tool for coming up with new sounds/processors, than as a virtual pedalboard.

"With only one knob, you don't get the sweet immediate tweakability of a pedal board, but then I guess you could (as I have done) send a MIDI controller into it with tonnes of knobs, which would give you back some of that tweakability. Anyways, its fun!"

Fun, ZOIA most certainly is. Some people are even calling it "the world's most powerful pedal", given the infinite possibilities contained therein.

Unsurprisingly, a pedal this complex has taken a lot of development to get anywhere near to what Bragg considers right. Quietly unveiled at the music trade show NAMM in January 2018 – and instantly setting the internet's audioheadz and gearslutz hearts aflutter – various mooted shipping dates came and went: "My predictions on when things will be ready are horrible," acknowledges Bragg.

Despite now being on public release, the development of ZOIA continues. There's no sense of 'out the door and we're done' at Empress. A number of their pedals are regularly updated with new firmware, easily installed via the SD card slot round the back of the pedal, adding cool new features and quoshing bugs, the information garnered from user feedback. Even to reach the point of public release, ZOIA went through many months of beta testing, after many months of in-house refinement.

"We thought we had our hands full with our Reverb and Echosystem products. The ZOIA puts those to shame in terms of complexity," Bragg recalls. "With the Reverb and Echosystem, there was hardly any dynamic memory allocation. With the ZOIA, we're allocating and freeing memory all over the place!

"Half way through development we were running into a situation, which I'm sure a lot of developers will be painfully aware of. We'd push some new feature to the main development branch and weeks later we'd notice some other feature wasn't working properly, so we'd spend hours hunting some bug that crept in weeks ago. So painful just to think about it!

"So we bought 'Test-Driven Development for Embedded C' by Grenning. It took a bit of work to set up, but we'd never go back. We have a couple hundred unit tests installed, everything gets tested after we write a new feature. So we are confident that if a commit is on the main branch, it passes all our unit and integration tests."

Even deciding what ZOIA should do out of the box posed Empress with a further conundrum, as Bragg explains: "A less technical but very important challenge we've had is what features to work on before release vs what features to leave until after release.

"ZOIA is the kind of product that is never finished. Our beta testing team had a lot of opinions on what features we should implement and what direction we should take the ZOIA in. We implemented a voting forum to get a general idea of what features were important. We then took those features and asked ourselves: Do we like this feature? How complex is it and how long would it take to implement? Is there a workaround if we don't implement this feature? How useful is it?

"I think working in this way has streamlined our development and led to a product that will be useful for a lot of different people."

As Bragg says, the germ of ZOIA originated in his use of the Pure Data visual programming language, developed by Miller Puckette in the 1990s for creating interactive computer music and multimedia works. Puckette's work is also related to Max/MSP, another visual programming language for music, in which modules, routines and libraries can be connected and combined almost infinitely – limited primarily by the processing power of the host CPU.

Bragg spent many hours deep in Pure Data (PD), using a Monome (an interactive instrument that allows the user to define its function, company motto: 'Sound machines for the exploration of time and space'), precisly to try and create a digital modular system that did away with the need to spend hours twiddling around in Pure Data.

"I love Pure Data, but since I program all day for work, the idea of creating patches in front of a screen doesn't appeal to me," Bragg says. "So the idea of ZOIA was to be able to create PD-like patches without a computer. In PD, you have objects; the analog in the ZOIA are modules. You place down modules on ZOIA's grid and connect them together in whatever way you want. No need for a computer!"

Bragg pauses for a second, reflecting, before self-correcting. "So I lied when I said there was no need to use a computer with the ZOIA, because there are actually two processors inside the ZOIA. One handles the audio processing and the other is dedicated to the user interface. This is a similar design to our Echosystem and Reverb, but with the ZOIA the user interface takes on a lot more importance.

"The audio processor not only processes audio but receives user actions from the UI processor and sends it to the LED and screen data. The UI processor unpacks this data and sends it off to the LED drivers and OLED. It's a nice decoupled system that is easy to test during development, which was one of our key concerns with creating the ZOIA."

While Empress Effects is known mostly by guitarists for being 'one of those cool boutique pedal companies' – lucky as we all are to be living in a golden age of creative zeal, free expression and exceptional quality in the effects pedal sphere – increasingly Empress products have been finding their way into the set-ups of synth players, loopers, on top of mixing consoles in the studio. The effects are no longer 'relegated' to the floor, waiting to be stomped on. Some of Empress' algorithms are so advanced and so refined that, hell yeah, why wouldn't you use, say, the Reverb pedal on a send bus of your mixing desk, so that multiple channels in your mix can benefit from a beautiful 'Plate' sound?

With this in mind, we wonder what the approach is for new product development at Empress. What are the design goals and aspirations?

"My answer is so boring, but I guess we want people to at least consider the product among the best in whatever it's doing," Bragg says. "That's been the goal for the first 10 years of Empress. Going forward, I think we'll care less about that and focus more on making interesting products. At least personally, after doing this for 13 years, I don't want to go back to working on another phaser.

"Of course, having said this, I'll probably look back in 2050 and wonder why we did that whole line of phaser pedals!" Bragg adds, laughing.

What are the typical design, engineering, and prototyping stages? Is there even a 'typical' workflow?

"It's seems like it's different with each product," Bragg replies. "We are kind of messy when it comes to project management. But I guess there's some common things. We end up making a lot of prototypes. For the Reverb we made six, I think. I'm not sure if a professional engineer (I never got my official designation) would gasp in horror at that number of revisions, or if they'd say 'That's nothin'!'"

"We sometimes make some pretty big changes to the UI, which necessitates a lot of hardware and software changes. I've attached a PDF of an early Reverb [pictured below] and also pics of all the Reverb UI board versions.

Empress Reverb circuit

Image credit: Empress Effects

"Sometimes we think we're ready with a product and take it to NAMM [the annual National Association of Music Merchants trade show, held in the US] and it turns out we're not. The big example is when we took our Tape Delay to NAMM and people were like, '$250 and no presets?' People were kind of blah about it. So we had to do a pretty big revision, adding presets and some other stuff."

At Empress, each major new pedal the company has launched has proven to be a springboard to the next major new pedal, as the (small) team builds on what they all learned from designing and engineering the previous product. One of the key pedals in this regard for Empress was 2010's Superdelay, Empress' first really complex 'big box' pedal, as Bragg recalls.

"Back in 2010 we started playing around with the idea of moving to a really powerful DSP processor. We had used a Microchip dsPIC for our Superdelay product and we were really stretching what it was capable of. In the Superdelay, the processor is overclocked and we had to optimise a bunch of the code in assembly to squeeze out all the processor cycles we could.

"Whatever processor we chose, it had to handle the most intensive audio processing tasks, so the obvious choice was a reverb product. Reverb effects typically require impulse responses for the early reflections and a lot of delay lines to sound natural. We eventually ended up settling on the Analog Devices Blackfin BF514 to run the reverb algorithm."

Bragg calls on Empress' algorithm wrangler Jason Fee to explain more about the process for Reverb.

"A challenging aspect of algorithmic reverb design is getting small rooms simulations to sound accurate," Fee says. "Algorithmic reverb typically uses feedback loops with all-pass filters to increase density over time, but with small room simulations you want a dense response very quickly for it to sound accurate. The first thing to try would be to shorten the loop lengths so that the density increases faster, but this tends to lead to a lot of resonances in the response which equates to a really metallic tone.

"Instead, we used an interesting approach in that we used an actual room impulse response, which we convolve with incoming signal for the first part of the tail, and then used an algorithmic reverb to provide the latter part of the tail. Getting the transition to sound right took a lot of finesse but the result is a very realistic small room sound."

In moving from Superdelay, via Echosystem, to Reverb, always with a third eye on future possibilities, Empress' approach of offering users a comprehensive suite of creative options out of the box, plus the ability to constantly update and expand the pedal's feature set via firmware updates, gradually fell into place, pointing a path to ZOIA.

"The Reverb was our introduction to using a complex DSP processor," Bragg explains. "Since I was handling a lot of the back-end, I spent a ton of time debugging peripheral issues. They always seem to be the most time-consuming issues. With software, you can set breakpoints, see what all your data looks like in a watch window, test hypothesises quickly.

"When your SD card isn't writing as fast as you need it to, you have to bust out the logic analyser, and the multimeter, and the scope. Then there are those issues where your code runs fine under an emulator, but booting it from flash fails once every 20 times.

"So you go down tonnes of rabbit holes, to finally discover some obscure 05-00-0490 anomaly! So my challenges really had nothing to do with the reverb aspect of the product. My challenges were 'Why does RAM suck? Why does the cache suck? Why is there a stack overflow? Why has the I2C stopped working?'"

All that hard benchwork seems to have paid off, the internet's pedal enthusiasts – of which there are legion – going gaga for the ZOIA. There are countless Instagram musician accounts now regularly posting short video clips of whatever fresh'n'freaky insanity they've created with a ZOIA, a Reverb and a MIDI keyboard. There haven't been many pedals that have created quite the revolution in the heads that ZOIA has triggered.

Crucially, for Empress and the rest of us, as much as for himself, Bragg is as enthused about effects pedals as ever. Reflecting on the huge variety of boutique pedal companies around the world, often just one or two-person operations, fellow aural astronauts exploring strange new frontiers in space and sound, Bragg is pretty happy with the state of affairs: "It does seem like a strange wonderful industry. It's nice that the market pie is so fragmented. Four companies own 50 per cent of the [guitar] amp market. By comparison, the top 10 best-selling pedals companies don't even own 50 per cent of the pedal market. That's nice!

"There are tonnes of pedal companies that come out of nowhere with a new idea that shakes things up and they sell enough to make a living. Making guitar pedals?!? Freaking mental!!"

Empress Effects ZOIA product page

Sign up to the E&T News e-mail to get great stories like this delivered to your inbox every day.

Recent articles